After considerable struggle I've completed the lower half of this rather difficult Xword.
I think my brain needs a kick or three, so help with the top three would be invaluable :
1A - Members bound to keep to themselves, even? (7)
???????
5A - Gradually, Post Office couple refusing to serve grasping pensioner (4,1,4)
???? ? ????
&
10A - Undergarment picked up for revel (4)
???K